Folding tone arm for a phonograph



Feb. 22, 1966 M. J. CAPPARELLI, JR 3,235,525

FOLDING TUNE ARM FOR A PHONOGHAPH Filed Oct. 50, 1963 FIG.I.

INVENTOR:

WQM HIS ATTORNEY.

MICHAEL J. CAPPARELLLJR.

United States Patent 3,236,526 FOLDING TONE ARM FOR A PHONOGRAPH MichaelJ. Capparelli, Jr., Rome, N.Y., assignor to General Electric Company, acorporation of New York Filed Oct. 30, 1963, Ser. No. 320,207 6 Claims.(Cl. 27423) This invention relates to an improved tone arm construction,and in particular to a foldable tone arm mechanism for use withphonograph records of the disc type.

In many phonograph applications it is important that the phonograph unitbe of very compact structure. To help achieve such a goal, it has beenfound desirable to provide a new and improved tone arm arrangement whichreadily lends itself to use in such a structure. Accordingly, animportant object of my invention is to provide an improved phonographtone arm mechanism which is readily foldable into a compactconfiguration when not in use.

Another object of my invention is to provide an improved folding tonearm construction wherein wiping contact engagement is utilized toachieve a foldable connection to a pickup cartridge.

An additional object of my invention is to provide an improved tone armconstruction which includes a pair of pivotally linked arms and one ormore pairs of wiping contacts carried by the arms to provide anuninterruped connection to a pickup cartridge during a predeterminedanlgular movement of one of said arms relative to the ot er.

In carrying out my invention, in one form thereof, I apply it to afolding tone arm mechanism which includes two pivotally associated armsand a pickup cartridge. A first one of the arms is supported at one ofits ends for pivotal movement in both vertical and horizontal directionsrelative to a turntable. The second arm is pivotally supported on thefree end of the first arm so that it may serve as an extension of thefirst arm for operation of the phonograph, or alternatively, it may foldback upon the first arm to provide a compact tone arm mechanism. Thepickup cartridge is secured to and supported by the free end of thesecond arm. To provide an effective electrical connection to the pickupcartridge, one or more wiping contacts is carried on one of the foldingarms and arranged to cooperatively engage an associated contact carriedby the other arm. Such a tone arm arrangement has been found to achievea very compact and efficient structure.

Further aspects of my invention will become apparent hereinafter, andthe specification concludes with claims particularly pointing out anddistinctly claiming the subject matter which I regard as my invention.The invention, as to organization and method of operation, together withfurther objects and advantages thereof, may best be understood byreference to the following description when taken in conjunction withthe accompanying drawing, in which:

FIG. 1 is a perspective view of a tone arm mechanism embodying one formof my invention;

FIG. 2 is an elevation view of the tone arm mechanism of FIG. 1 inoperation, with part of the supported end thereof not shown, forpurposes of simplicity;

FIG. 3 is a bottom view of the arm mechanism of FIG. 2;

FIG. 4 is an elevation view of a tone arm mechanism embodying myinvention in alternate form thereof;

FIG. 5 is a bottom view of the tone arm mechanism of FIG. 4; and

FIG. 6 is an elevation view of the tone arm shown in FIG. 1, with theoutermost arm folded into retracted position.

Referring now to the drawing, and at first to FIGS. 1 and 2 thereof,there is illustrated a foldable tone arm mechanism 1 embodying one formof my invention. The tone arm mechanism 1 includes a first elongated arm3 pivotally supported upon a bearing assembly 5, a second arm 7pivotally supported on the free end 9 of the first arm 3, and a pickupcartridge 11 secured to free end 13 of the second arm 7.

The bearing assembly 5 is mounted upon an L-shaped supporting tube 15,and it includes a tone arm support 17 which swivels about a sleeve 19.The sleeve 19 cooperates with a reduced upper end 21 of tube 15. Thetone arm support 17 is thus arranged to rotate about an axisperpendicular to the turntable (FIG. 2). Support 17 also includes a pairof apertured uprights 23 which rotatably receive and support a bearingpin 25 secured to the supported end of arm 3. The pin 25 is arranged inthe uprights 23 of tone arm support 17 so that the arm 3 is permitted torotate vertically in conventional fashion, about an axis parallel to thesurface of the turntable.

For the tone arm mechanism 1, the arms 3 and 7 are each constructed froma rigid and sturdy acetal resin insulative material, as for example, oneof the superpolyoxymethylenes.

Turning now to an important aspect of the present invention, whichconcerns itself with an improved means for enabling the tone armmechanism 1 to be compactly folded when not in use, attention isdirected to the left side or free end 9 of the elongated arm 3, as shownin FIGS. 1-3. At free end 9 of the arm 3 there is formed a hub 29. Hub29 has a downwardly facing bearing contact with a contiguous upwardlyfacing surface of the pivotally supported end 31 of arm 7. Moreparticularly, the hub 29 may include housed therein a plurality of ballbearings (not shown) for bearing engagement with the upwardly facingsurface on end 31 of arm 7 (viewing FIG. 2). The arm 7 is held inrotatably supported engagement with arm 3, by means of screw 33 which isextended through aligned apertures of hub 29 and arm end 31, andthreaded into engagement with hexagonal nut 35 (FIG. 3). The screw 33may be readily adjusted into engagement with its associated nut 35 toobtain the desired amount of frictional engagement between the arms 3and 7. For normal operation of tone arm mechanism 1, arm 3 is infrictional engagement with arm 7, and arm 7 does not pivot with respectthereto.

To eliminate any need for bending wires connected to the pickupcartridge 11 carried by pivotally supported arm 7, in accordance with myinvention there is provided a foldable electrical connection afforded bytwo pairs of wiping contacts 37 and 39 (FIG. 3). More particularly, asbest shown in FIG. 2, on the bottom surface 41 of the insulative arm 3,near the free end 9 thereof, there is secured a pair of spaced apartconductive shoes 43 and 45.

The shoes 43 and 45 are spaced apart laterally on the tone arm 3, andthey each include a generally arcuate body section having a smoothbottom surface 47 disposed in a plane perpendicular to the axis ofrotation of arm 7 with respect to arm 3. The smooth bottom surfaces 47of the conductive shoes 43 and 45 are in electrical and mechanicalengagement with the upwardly directed and resiliently biased looped ends49 and 51 of a pair of associated springs 53 and 55 to provide the twopairs of wiping contacts 37 and 39.

The springs 53 and 55 have the general configuration of bent overhairpins. More particularly, springs 53 and 55 each include thevertically arranged U-shaped loop 49 (FIG. 3) or 51 (FIG. 2) and a pairof supporting arms 49a or 51a (FIG. 3) which are bent over from their associated loops into a direction generally parallel to the longitudinalaxis of arm 7. Each pair of the supporting 3 arms 49a and 51a issuitably secured into fixed electrical engagement with one of a pair oflaterally spaced apart and elongated conductive shoes 63 and 65 attachedto the bottom surface of arm 7 near its end 31.

It will now be seen that two wiping connections are thus provided forthe folding tone arm mechanism 1, by means of the resilient brush-typeengagement of the looped ends 49 and 51 of the springs 53 and 55 withthe smooth surfaces 47 of the conductive shoes 43 and 45. When the arms3 and 7 of the tone arm mechanism are in the pivoted relationshipwherein they are shown in FIG, 3, an electric circuit is thereuponestablished from the amplifier (not shown) to the pickup cartridge bymeans of a conductor 67 (disposed underneath arm 3), through conductiveshoe 45, contact wiping spring 55, elongated contact shoe 65, conductorlead 69 (underneath arm 7), terminals 71 and 73 of the pickup cartridge,conductor lead 75 (underneath arm 7), elongated contact shoe 63, wipingcontact spring 53, conductive shoe 47, and conductor 77 (underneath arm3).

The pickup cartridge 11 may be of any suitable variety. In the tone armmechanism 1, which illustrates one embodiment of my invention, pickupcartridge 11 supports a drive rod 79 (FIG. 3) that carries a singlestylus 81 (FIG. 2) on its bottom end. Cartridge 11 may be suitablysecured to the bottom surface of arm 7 near its free end 13 by means ofa V-shaped bracket 83 which has secured thereto a pair of gripping arms.

As further shown in FIG. 2, the tone arm mechanism 1 is readily operablewith the arms 3 and 7 in extended position (i.e. with their longitudinalaxes generally aligned and the arms extended outwardly from each other)to reproduce the sound of a disc type of record 85 rotatably supportedon a turntable 87. In the event that it becomes desirable to retract thearm 7, for the purpose of making the mechanism 1 more compact, arm 7 issimply rotated about its pivot with respect to arm 3 for approximately180 degrees, until it underlies arm 3, as indicated in FIG. 6. Theamplifier circuit to the pickup cartridge 11 is thereupon de-energized,since the contact springs 53 and 55 are disconnected from theirassociated shoes 43 and 45. It will thus be realized that with a minimaleffort, a relatively small tone arm mechanism is achieved, thus lendingitself to convenient and expeditious storage.

FIGS. 4 and represent a modified form of my invention wherein tone armmechanism 101 has been employed. For mechanism 101, the same referencenumerals have been employed to indicate parts which have been describedheretofore for mechanism 1.

Parts of mechanism 101 which have a modified structure in comparison tothe structure of certain correlative parts for mechanism 1, but performthe same basic function, are identified by the same two referencenumerals, with the numeral 1 prefixed thereto.

The basic difference between tone arm mechanism 101 and mechanism 1resides in the fact that the arms 3 and 7 of mechanism 101 areconstructed of conductive material, While the arms 3 and 7 of mechanism1 are of insulative material. Since arms 3 and 7 of mechanism 101 areconductive they are utilized in the amplifier circuit for the pickupcartridge 11, and consequently only one pair of wiping contacts 137 isrequired for the foldable tone arm mechanism. More particularly, arm 3of mechanism 101 has a single enlarged arcuate conductive shoe 143 Witha smooth bottom surface 147 for engagement with the spring biased loopedend 149 of spring 153. Shoe 143 is secured to the underside of arm 3near its free end 9, with an insulating spacer 144 located between thearm 3 and shoe 143. The spring 153 is similar in configuration,construction and arrangement to the springs 53 and 55 and it functions,in the same manner. More particularly, spring 153 includes the loopedend 149 and supporting arms 149a. The arms 149a are suitably secured toan arcuate outer surface of an enlarged conductive shoe 4 163. Shoe 163is secured to the underside of the free end 31 of arm 7, but spacedtherefrom by insulating. spacer 164.

When the arms 3 and 7 of the tone arm mechanism! 101 are in the pivotedrelationship wherein they are: shown in FIGS. 4 and 5, an electriccircuit to pickup' cartridge 11 thereof is thereupon established fromthe amplifier by means of the series connection of conductivearm 3,conductive arm 7, arm terminal 166, lead 175,. terminals 173 and 171 ofthe pickup head, lead 169, con-- ductive shoe 163, spring 153,conductive shoe 143, and lead 167.

The tone arm mechanism 101 retracts in the samemanner as illustrated formechanism 1, for convenient: storage, when it is not in operation.

It will now, therefore, be seen that my new and im-- proved foldabletone arm mechanism provides an effective Wiping contact arrangement. Itwill also be understood. that tone arm mechanisms embodying my inventionare: of very compact structure, thereby readily lending them-- selves toefficient utilization for phonograph applications; requiring economy ofspace.

While in accordance with the patent statutes, I have described what atpresent are considered to be the pre ferred embodiments of my invention,it will be obvious. to those skilled in the art that various changes andmodi' fications may be made therein without departing frommy invention,and I, therefore, aim in the following: claims to cover all suchequivalent variations as fall within the true spirit and scope of thisinvention.

What I claim as new and desire to secure by Letters; Pattent of theUnited States is:

1. A folding tone arm mechanism for a phonograph,. said mechanismincluding a first element, a second ele-- ment, and a pickup cartridge;said first element supported for movement in vertical and horizontaldirections rela-- tive to a normal position of said first element; andmeansfor pivotally supporting said second element upon saidl firstelement for movement about a vertical axis to enable said second elementto selectively serve as an ex-- tension from the free end of said firstelement for operation of said phonograph or to be folded back into com--pact proximity with said first element when said phono-- graph is not inuse; said pickup cartridge disposed upon. the free end of said secondelement; and means for con-- meeting said cartridge to said phonograph,said means; including at least one wiping contact on one of said elements for cooperative engagement with a mating contact: on the other ofsaid elements, thereby to provide a fold-- able electrical connection tosaid pickup cartridge on said. tone arm mechanism.

2. The folding tone arm mechanism of claim 1 wherein the wiping contactis a generally V-shaped spring and. its mating contact is a relativelyflat conductive shoe, said spring including a looped end biased intoresilient. cooperative engagement with said shoe.

3. A folding tone arm mechanism for a phonograph, said mechanismincluding a first element, a second element, and a pickup cartridge;said first element supported at one of its ends for movement in verticaland horizontal. directions relative to a normal position of said firstele-- ment; means for pivotally supporting said second ele-- ment upon afree end of said first element for movement about a vertical axis toenable said second element to selectively serve as an extension from thefree end of said first element for operation of said phonograph or to befolded back into compact underlying proximity with said first elementwhen said phonograph is not in use; said pickup cartridge disposed uponthe free end of said second element; and means for connecting saidcartridge to said phonograph, said means including at least one wipingcontact on one of said elements for discontinuous cooperative engagementwith a mating contact on the other of said elements, thereby to providea foldable electrical connection to said pickup cartridge on said tone.arm mechanism.

4. The tone arm mechanism of claim 3 wherein said first and secondelements are of insulative material and said connecting means includes apair of wiping contacts engaging a respective pair of mating contacts.

5. The tone arm mechanism of claim 3 wherein said first and secondelements are constructed of conductive material and said connectingmeans includes one wiping contact for cooperative engagement with onemating contact.

6. The tone arm mechanism of claim 3 wherein the second element isgenerally parallel to the first element when said second element is inunderlying proximity to said first element, said second element beingrotatable upon said first element through an angle of approximately 180from its normal operative position to its compact position.

References Cited by the Examiner UNITED STATES PATENTS 1,742,257 1/1930Johnson et a1. 27423 2,116,050 5/1938 Stock et al. 240-73 2,595,6215/1952 West et a1 310-232 3,120,393 2/1964 Pennucci 240-23 NORTONANSI-IER, Primary Examiner.

C. B. PRICE, Assistant Examiner.

1. A FOLDING TONE ARM MECHANISM FOR A PHONOGRAPH, SAID MECHANISMINCLUDING A FIRST ELEMENT, A SECOND ELEMENT, AND A PICKUP CARTRIDGE,SAID FIRST ELEMENT SUPPORTED FOR MOVEMENT IN VERTICAL AND HORIZONTALDIRECTIONS RELATIVE TO A NORMAL POSITION OF SAID FIRST ELEMENT; ANDMEANS FOR PIVOTALLY SUPPORTING SAID SECOND ELEMENT UPON SAID FIRSTELEMENT FOR MOVEMENT ABOUT A VERTICAL AXIS TO ENABLE SAID SECOND ELEMENTTO SELECTIVELY SERVE AS AN EXTENSION FROM THE FREE END OF SAID FIRSTELEMENT FOR OPERATION OF SAID PHONOGRAPH OF TO BE FOLDED BACK INTOCOMPACT PROXIMITY WITH SAID FIRST ELEMENT WHEN SAID PHONOGRAPH IS NOT INUSE; SAID PICKUP CARTRIDGE DISPOSED UPON THE FREE END OF SAID SECONDELEMENT; AND MEANS FOR CONNECTING SAID CARTRIDGE TO SAID PHONOGRAPH,SAID MEANS INCLUDING AT LEAST ONE WIPING CONTACT ON ONE OF SAID ELEMENTSFOR COOPERATIVE ENGAGEMENT WITH A MATING CONTACT ON THE OTHER OF SAIDELEMENTS, THEREBY TO PROVIDE A FOLDABLE ELECTRICAL CONNECTION TO SAIDPICKUP CARTRIDGE ON SAID TONE ARM MECHANISM.